1. Field of the Invention
The present invention relates to an automatic power disconnection of a battery, and more particularly to an automatic battery-overcharge power disconnection device and a battery having the automatic battery-overcharge power disconnection device.
2. Description of Prior Art
As mobile electronic devices become popular and have a high performance, a high-capacity battery is required and expected, and thus a lithium-ion battery using electrochemically doped lithium and dedoped carbon materials as an active substance for a negative electrode and lithium-containing transition metals as an active substance for a positive electrode is used extensively.
However, if such secondary lithium battery is overcharged, extra lithium ions will be extracted from the positive electrode, and an insertion of extra lithium ions will occur at the negative electrode to release lithium metal and form a very unstable high-performance oxide at the positive electrode side. When the battery voltage of the overcharged battery rises to a specific voltage value, an organic solvent in an electrolyte solution is decomposed to produce a large quantity of combustible gas and causes a rapid heat generating reaction and an abnormal heat generation of the battery. Obviously, such secondary lithium battery has a safety issue. In view of the aforementioned reasons, the inventor of the present invention based on the aforementioned subject to make novel improvements.
In a conventional protection structure for rechargeable batteries as disclosed in Taiwan Pat. Nos. M292169 and M275625 issued to the inventor of the present invention, a lithium battery protection structure as disclosed in Taiwan Pat. No. M292169 comprises an abnormity detection circuit and an optical coupler circuit, wherein the abnormality detection circuit is provided for examining the voltage of a rechargeable battery and outputting a detect signal, and the optical coupler circuit is electrically coupled to the abnormality detection circuit for adjusting an impedance of the optical coupler circuit according to the detect signal to disconnect the rechargeable battery from the connection of an external circuit or to charge or discharge the rechargeable battery. In addition, a protection structure for a rechargeable battery as disclosed in China Pat. No. M275625 comprises a first protection loop and a second protection loop, wherein the first protection loop includes a main current load and a battery connected to a main circuit, and a thermocouple induction switch connected to the battery and the main circuit, and the second protection loop includes a protection circuit and a heater, and the protection circuit is connected to the main circuit for detecting and comparing a voltage value of the battery to output an ON signal, and the heater is connected to the protection circuit for performing a heating operation when the thermocouple induction switch is turned on. At present, a mechanical protection device is used mostly in a cylindrical hard-shell lithium battery, such that if the lithium battery is overcharged, an internal pressure will be increased to start the operation of a pressure release valve to release the pressure and break the conductive handle in the battery.
Although the aforementioned overcharge protection structure of the lithium battery has the function of protecting the battery from being overcharged to a specific level, the components and circuits will be damaged or worn out and will lose their original functions after a long time of use. Furthermore, the mechanical safety protection device of the cylindrical hard-shell lithium battery cannot be used in a soft-shell lithium battery, and each of the foregoing protection structures or devices requires complicated and troublesome assembling and installation. Therefore, it is a main subject for the present invention to disconnect the power of a battery safely when any component or circuit is damaged and to overcome the issue of a high price by using a simple structure.
In view of the shortcomings of the prior art, the inventor of the present invention based on years of experience in the related field to conduct extensive researches and experiments, and finally developed an automatic battery-overcharge power disconnection device and a battery thereof in accordance with the present invention and provide a feasible effective solution to overcome the shortcomings of the prior art.